Clean Harbors Inc., the Norwell-based environmental services company best known for cleaning Superfund sites, oil spills, and some of the nation’s worst natural- and man-made disasters, is now helping make greener one of the world’s most popular sports: NASCAR.

Nearly a year after acquiring Safety-Kleen Systems Inc., which recycles oil from race cars, Clean Harbors is trying to build on that foothold to promote its own brand among NASCAR’S racing franchises and corporate sponsors who might need its other environmental services.

“Some of these events bring out 100,000, 150,000 people at a time,” said Clean Harbors chief executive Alan S. McKim, whose company purchased Safety-Kleen for $1.25 billion in cash in late 2012. “So you’re talking about millions of people that you can have a direct impact with, and getting your name out there and your reputation.”

Safety-Kleen’s services are used at over 65 race tracks in North America. The firm recycles more than 200,000 gallons of oil used during 200-plus NASCAR-sanctioned races each year, including the annual summer event at the New Hampshire Motor Speedway in Loudon, N.H.

The oil recycler will continue to operate under the Safety-Kleen name at NASCAR but will be promoted as a unit of Clean Harbors, with the aim of raising the Norwell company’s profile among corporations that sponsor race cars.

Many of those corporations are big generators of waste, McKim said, making them potential customers for Clean Harbors’ other divisions, which handle hazardous materials, solid waste disposal, product shredding, and cleaning contaminated properties. So the more they interact with Safety-Kleen, the more they might consider Clean Harbors for those other services, McKim said.

“Down the road, we want Clean Harbors to have sort of the same name recognition across those 200,000 customers that Safety-Kleen now has,” McKim said. “We want them to think about Clean Harbors in terms of their [overall] environmental response.”

Clean Harbors began as a four-man oil-tank-cleaning firm founded by McKim in 1980. His growth strategy has been to become bigger by buying companies with operations that complement other services Clean Harbors already offers. The purchase of Safety-Kleen, the largest re-refiner of waste oil in North America, was just such an opportunity for Clean Harbors, he said, helping it to expand its waste-disposal and treatment offerings.

That deal, among others, has helped Clean Harbors grow into a company with nearly $2.2 billion in revenue and more than 13,000 employees in the United States and Canada, including 900 in Massachusetts, at the end of 2012.

For its part, Safety-Kleen has worked with NASCAR since 1987, but remained largely in the background until five years ago.

That’s when the racing association launched NASCAR Green, an environmental program aimed at reducing the sport’s impact on the environment — particularly given the amount of fuel used during track events.

Under NASCAR Green, racing vehicles now run on Sunoco Green E15, a gasoline-biofuel blend made with 15 percent ethanol, while Safety-Kleen has collected and re-refined enough used motor oil to power the Empire State Building for a year. The recycled oil is used in track vehicles.

“In other sports, it’s natural to recycle beverage containers — that’s straightforward — at all your events, then add cardboard,” said Mike Lynch, managing director of green innovation at NASCAR. “What we have in our garage is a range of materials that need to be recycled that Safety-Kleen and Clean Harbors can help us with,” including automotive fluids, tires, and batteries, as well as motor oil.

Such efforts, NASCAR representatives say, have the power to “really move the needle” on environmental stewardship, a cause that they acknowledge helps change some people’s perception of racing as little more than a gas-guzzling, polluting pastime.

Why could the sport have so much influence? NASCAR’s fan base — tens of millions of people in the United States — have long been known as a loyal group whose buying habits favor the sponsors of their chosen drivers, earning the sport the unofficial slogan, “Win on Sunday, sell on Monday.”

That means when fans see NASCAR promoting environmental initiatives or the services of outfits like Safety-Kleen and Clean Harbors, it often results in those consumers talking, and ultimately, using their buying power to take action, Lynch said.

“That gets them asking their mechanic, when they’re getting their oil changed, ‘Hey, where is my oil going? Is it going to Safety-Kleen?’ ” Lynch said. “Good enough for NASCAR, good enough for them.”

Environmental advocates, such as Allen Hershkowitz, a senior scientist at the Natural Resources Defense Council, meanwhile, agree that NASCAR’s efforts could be a boost for the movement.

NASCAR’s top racing series for the Sprint Cup, which ended its season Sunday, attracts some 3.8 million fans to 38 events. NASCAR has 100 million television viewers, according to Nielsen ratings from the racing powerhouse.

”The environmental community needs help, we need help reaching Americans — big time — and NASCAR is offering us that opportunity,” said Hershkowitz, who directs the defense council’s efforts to help make sports and entertainment franchises greener, and often works with NASCAR. “They’re recycling millions of gallons of oil, they’re recycling millions of tires . . . and they’ve got millions of fans watching. Why would you be cynical about this?”